Omeprazole is a proton pump inhibitor that regulates the final step in hydrogen ion production and blocks gastric acid secretion in the gastrointestinal tracts of mammals. Omeprazole is used in mammals to treat peptic ulcers, dyspepsia and gastroesophageal reflux disease among other conditions. Omeprazole is effective because it acts to provide a long lasting reduction of gastric acid production.
Proton pump inhibitors, such as omeprazole, act by irreversibly blocking the hydrogen/potassium adenosine triphosphatase enzyme system (H+/K+ ATPase) of the gastric parietal cell. The proton pump is the terminal stage in gastric acid secretion and is directly responsible for secreting H+ ions into the lumen of the stomach. The lack of acid in the stomach lumen aids in the healing of duodenal ulcers, reduces the pain from indigestion and reduces the frequency and severity of heartburn.
Currently, omeprazole for oral administration is provided in paste form for veterinary use. This paste is a thick consistency which does not flow without an applied pressure, similar to a thick toothpaste. The prior art teaches a 37% omeprazole in paste form with a typical dosage unit containing approximately 2.28 grams omeprazole. The prior art paste provides about a 10.5% bio-availability. The prior art paste also contains a hydrophobic oily liquid vehicle as an inert filler aiding the isolation of the omeprazole from moisture. This hydrophobic oily liquid is used as a carrier for dispersing the active omeprazole in the formulation before the addition of a thickening agent. The prescribed oral dose of the product is 4 mg/kg, once daily for four weeks. The solubility of omeprazole is 0.5 mg/mL in water, >19 mg/mL in dimethyl sulfoxide (DMSO), 20 mg/mL in Polyethylene Glycol 400 and 4.5 mg/mL in ethanol. Omeprazole is not very stable in water, ethanol or in acidic environments. Omeprazole decomposes rapidly at pH levels below about 4, with a half-life at neutral pH of about 14 hours. Omeprazole is very stable at pH levels above 7 if it protected from light and extremes in temperature and humidity. The drug is delivered in a paste or solid dose form in the prior art because of the instability of omeprazole in the presence of moisture.
What is desired is an oral solution or syrup formulation of omeprazole as a single or multi-dose application for use in the veterinary field.